Effect of N2 anneal on thin HfO2 layers studied by conductive atomic force microscopy

The effect of thermal annealing on the electrical properties of thin HfO2 layers was studied by conductive atomic force microscopy. Based on high resolution (10 nm) current maps it is possible to observe the transition from a homogeneous current distribution for the non-annealed case towards the presence of electrical weak spots in the annealed samples. Although the current density in the weak spots can reach 20 A/cm(2), local I-V curves indicate that not all of them are acting as a real breakdown spot. The weak spots density observed is around 10(10)-10(11)/cm(2), which represents 5-10% of the scanned area. (C) 2004 Elsevier B.V. All rights reserved.